1. Technical Field
The present disclosure relates generally to universal serial bus (USB) host systems and, more specifically, to security arrangements for an extended USB protocol stack of a USB host system.
2. Background Information
Over the past 15 years, USB has emerged as the preferred, if not dominant, technology for interfacing personal computers (PCs) or other host systems with a wide variety of devices including mass storage, smartphones, digital cameras, media players, keyboards and the like. Users enjoy the convenience and simplicity of USB, while manufacturers and software developers enjoy the benefits of having a single standard interface to support, although there are several different USB specifications that include different speeds.
While the USB protocol has proved sufficiently robust for typical user data transfers over short distances, the protocol does not include any security features to prevent or limit the effects of malicious activity originating from a USB device. For example, the USB protocol for wired communication does not require authentication of a USB device before permitting communication between the device and a host system. Thus, if a wired USB device identifies itself to a host system and the host has the appropriate driver available for that device, communication is established and the USB device is simply presumed to be non-malicious. Consequently, an unauthorized or malicious user could gain access to, disable or otherwise interfere with a host system by programming a USB device to launch an attack, deliver a virus, download data from the host system and the like.